There are a variety of reasons to lay cable, wire or hoses along a landscape or over a series of structures. For example, large amounts of cable and wire may be required to be laid for use with geophysical measurement techniques and methods. The laying of large amounts of cable is also required when hoisting power lines on top of a series of support structures.
Typical ways to lay cable and wire along a landscape can be a labour intensive process depending on the amount and type of cable required. Many organizations invest much time and resources to lay large amounts of cable. Typical ways to lay cable along the ground involve personnel manually spooling out cable while travelling by foot. This may involve using winders that hold spools holding from 100 m to 1000 m of cable. 1000 m of 10 AWG wire weighs approximately 160 lbs and is very difficult to transport by foot. Cable deployment for use with geophysical measurement techniques and methods could take a full day and several personnel members to complete.
Certain areas where cable and wire are to be deployed may be challenging for personnel traveling by foot or land vehicle as a result of the terrain and conditions of the landscape. For example, rocky terrain or densely treed landscapes tend to be areas that can be difficult for personnel that are deploying and laying cable or wire. These type of areas could increase the time for the cable laying process significantly and this can play a significant role for costs. Furthermore, safety issues are usually concerned when such areas are involved.
One way to overcome some of the problems associated with laying cable or other lengths of flexible material is to lay the material from the air. Devices have been developed that are configured to be attached to an aircraft. These devices which are capable of deploying cable for this purpose as well as the aircraft that they are attached to are airborne, thus the many problems as a result of land travel are not present. Furthermore, since an aircraft is supporting the weight of the device and the corresponding cable to be deployed, instead of personnel, larger spools of cable can be used.
For example, airborne systems have been designed for the purpose of laying large amounts of wire (up to 10 km of 10 AWG tracer wire) from a helicopter, therefore reducing the need for ground labor. The wire is loaded onto large wooden or aluminum spools/drums and then tied off on the ground at the start of the proposed wire deployment route. A helicopter long-line is hooked to the device and the device is hoisted off the ground via helicopter and transported, while spooling off wire, in a desired direction, generally following a prepared GPS route utilizing an onboard GPS system. Wire can be deployed using such devices at speeds of up to 20 km/h meaning that 10 km of wire can be laid out in a process that takes approximately 30 to 40 minutes.
It has been found, however, that many airborne devices, as described above, suffer drawbacks.
For example, airborne cable laying devices tend to over spool cable when the speed of the aircraft, to which the device is attached, is decreased. This occurs due to the rotational momentum of the spool as the aircraft slows down causing excess cable to be deployed resulting in slack. Too much cable slack can potentially result in tangling of the cable.
Airborne cable laying devices may be classified as a class C load if the cable is connected to the ground. Typically, in emergency situations that require urgent action, such as engine failure, the pilot would simply jettison the load. This involves disconnecting the airborne cable laying device from the aircraft and letting it fall to the ground, most likely damaging the device. The falling device may also damage property or result in personal injury to individuals on the ground.
Furthermore, winding up large quantities of cable from the field back onto a spool can be time consuming and difficult due the weight of the deployed cable.
What is needed, therefore, are aerial cable laying devices that address the problems described above.